The present invention relates to a portable lathe device and particularly to a lathe device that is modular in construction.
Portable machine tools are adapted to be mounted on or proximate the work to be machined rather than requiring the work to be transported to a stationary tool. Thus in pipeline applications the machining of flange faces on large sections of pipe can be more easily accomplished in the field since it is often difficult or impossible to disconnect pipe sections for transport to a machine shop. The same problem occurs in the machining of large parts and housings utilized in nuclear power plants, ocean going vessels, or for that matter in any application where the component to be machined is exceptionally large or difficult to move.
Portable flange facing devices are available which mount either on the inside diameter of a pipe or similar object or on the outside diameter thereof. The inside mounting type of course requires sufficient interior space within the work piece for receiving the tool and this type of mounting does not allow machining down to the "center" of a flange. On the other hand, exterior mounting devices frequently include a bearing which is larger than the diameter of the flange to be machined and are advantageously of heavy construction in order to avoid distortion of the tool during operation and resulting inaccuracies in finishing.
A central spindle machine carrying a cutting tool interiorly of a mounting bell, positioned exteriorly of the work, has the ability to face from the center of a flange outwardly while also providing stable support and drive for the cutting tool. However, machines of this type are restrictive in their capabilities. Usually, the axial movement of the cutting tool is limited and access to the work surface being machined is restricted. Furthermore, automatic tool feed, radially across the flange being finished, tends to be complicated and non-adjustable. An example of a tool of this type is illustrated in Hasund U. S. Pat. No. 3,273,432.
Furthermore, portable machine tools are quite specialized, not only as to purpose but as to the actual size of the work which can be accomodated. A portable tool adapted for flange facing is generally not usable for boring, or vice versa, and an entirely different machine tool would be used in facing a large flange as compared with a small flange.